1. What is Inrush Current?

Inrush current is the instantaneous high current that flows when a capacitor is initially charged. It occurs due to the low initial resistance (ESR) of the capacitor when it's discharged.

2. How Does the Calculator Work?

The calculator uses the inrush current formula:

Where:

• \( I_{inrush} \) — Inrush current (amps)
• \( V \) — Applied voltage (volts)
• \( ESR \) — Equivalent series resistance (ohms)

Explanation: The equation shows that inrush current is directly proportional to the applied voltage and inversely proportional to the ESR.

3. Importance of Inrush Current Calculation

Details: Calculating inrush current is crucial for designing protection circuits, selecting appropriate fuses, and preventing damage to power supplies and capacitors.

4. Using the Calculator

Tips: Enter voltage in volts and ESR in ohms. Both values must be positive numbers. The calculator will compute the peak inrush current.

5. Frequently Asked Questions (FAQ)

Q1: Why is inrush current important?
A: High inrush currents can damage components, trip circuit breakers, or cause voltage drops in power systems.

Q2: How can I reduce inrush current?
A: Common methods include using current-limiting resistors, NTC thermistors, or soft-start circuits.

Q3: Does capacitor size affect inrush current?
A: While capacitance doesn't appear in the basic formula, larger capacitors typically have lower ESR, which can lead to higher inrush currents.

Q4: Is this calculation valid for all capacitor types?
A: The formula applies generally, but ESR varies significantly between capacitor types (electrolytic, ceramic, film, etc.).

Q5: What safety precautions should I take?
A: Always use appropriate current-limiting devices and ensure your power supply can handle the peak currents.